Question

I am looking at using the facebook SDK and I am wondering first what version should I be using?

It looks like some major changes are happened from 4.2 to 5(currently still in beta). Should I go ahead and use the beta? Anyone have any ides when it will be out of beta?

My second question is how can I use it for authentication.

Right now I am using DotNetOpenAuth to do all my openId authentication for my site. I am using there sort of plugin for facebook authentication(oAuth) however I am planning to use more facebook features on my site so I think it is kinda pointless to use this plugin and then the sdk libary when the library seems to be able to do it all.

Anways how do I do authentication with the sdk library. I want to have a button on my login page that they click it goes off to facebook they become authenticated and I get some request back saying that they where authenticated and then I give them a cookie and let them in.

All the tutorials I seen to have it that your just using facebook as your only authentication method but of course for me I have openId, facebook and twitter.

http://facebooksdk.codeplex.com/wikipage?title=Getting%20Started%20with%20an%20ASP.NET%20MVC%203%20Website&referringTitle=Getting%20Started

Answer 1

Regarding 4.2 vs 5.0 BETA I guess you need to decide whether you want to use a BETA version or a stable version. I am sure they have a changelog in their BETA Release you can look at for the changes since the older version.

Regarding authentication using Facebook. I have a project where I support standard Forms authentication and accounts creation as well as Facebook login. In my AccountController I have one action for Forms login and one for Facebook login.

To configure the Facebook assembly you can follow the tutorial you have posted, then you can put a Facebook button on your page and similar code to begin the authentication process:

<script type="text/javascript" src="http://connect.facebook.net/en_US/all.js"></script>
<script type="text/javascript">
    $(function () {
        FB.init({ appId: '<%= FacebookSettings.Current.AppId %>', status: true, cookie: true, xfbml: true });

        $('#fbLoginButton').click(function () {
            FB.login(function (response) {
                if (response.session) {
                    // Success - execute our facebook login action.
                    window.location = "<%= Url.Action("FacebookLogin", "Account") %>";
                } else {
                    // user cancelled login or failed
                }
            }, { perms: 'email' });

            return false;
        });
    });

The facebook aciton works by:

1. Was Facebook Authentication successful?
2. Do we have a user with the Facebook Id as a username in the system?
3. If not create a user, populate name, email, etc from the Facebook data
4. Set the Forms authentication cookie

Pseudo code:

FacebookApp facebook = new FacebookApp ();
if (facebook.IsAuthenticated) {
        string userName = facebook.UserId.ToString();

        if (UsersRepository.ByUserName(userName ) == null) {
            // Create a User using the Facebook name, email, etc data
        }            
        FormsAuthentication.SetAuthCookie (userName , true);
}

So the idea is that I delegate the authentication to those 3rd party services and then create a user on my system with the information I can fetch from them. Also in my project, because I want the user to set/very some preferences after the account is created I redirect them to the page where they can do that.

P.S: A tip regarding running your web project locally in Visual Studio. You can create a private Facebook App with “Site URL” set to e.g. “http://localhost:4911/” and use that appId. This will allow you to play with Facebook locally.